It's unfortunate that it took an injury to the team's best setup man for this to happen, but with Casey Fien headed to the disabled list the Twins have called upMichael Tonkin from Triple-A. Rochester's bullpen is packed with intriguing relievers, several of whom look like better options than members of the Twins' bullpen, but based on the combination of minor-league track record, major-league track record, and raw stuff Tonkin appears to be the best bet.

Known first as Jason Kubel's brother-in-law, then as a decent starter prospect, and now as a good reliever prospect, Tonkin has thrived since shifting to the bullpen full time in 2011 and the 6-foot-7 right-hander should have cracked the Opening Day roster rather than be sent back to Rochester for a third straight season at Triple-A. By the time Fien is ready to pitch again hopefully Tonkin will have convinced the Twins he's ready to stay in Minnesota for good.

Tonkin is huge and throws hard, averaging 94 miles per hour with his fastball in the majors, but unlike most reliever prospects who fit that description he actually throws strikes too. Overall at Triple-A he's handed out just 18 non-intentional walks in 85 innings along with 92 strikeouts and just six homers allowed for a 3.39 ERA. And when given a chance in the majors he's logged 30 innings with a 3.26 ERA and 26/9 K/BB ratio.

His fastball is late-inning caliber, his mid-80s slider generates lots of swinging strikes, and at age 25 there's no reason for Tonkin to continue dominating Triple-A hitters for another season. Fien's shoulder injury leaves the bullpen without its only reliable setup man and we've already seen how ugly things can get when that happens this season, but Tonkin has the potential to be as good or better than Fien and it's well past the time for the Twins to give him an extended opportunity.

This also seems like a good time to appreciate the good work Fien has done for the Twins since they signed him to a minor-league deal in 2012. At that point he was a 27-year-old journeyman with 14 runs allowed in 14 innings as a big leaguer, but Fien's minor-league track record showed he was capable of more and sure enough he emerged as a durable, strike-throwing reliever with more bat-missing ability than his modest raw stuff suggested.

Called up in mid-2012, he's logged 171 innings with a 3.59 ERA and 159 strikeouts versus 24 non-intentional walks. As an extreme fly-ball pitcher Fien has some issues keeping the ball in the ballpark, but 20 homers allowed in 686 plate appearances isn't terrible and he's held opponents to a .235/.268/.379 line while being equally effective against righties and lefties. Among all Twins relievers with at least 100 innings since 2000 he ranks first in walk rate and K/BB ratio.

• He's still not showing any power, but Joe Mauer is doing his usual thing (.299 batting average, .392 on-base percentage, 11/11 K/BB ratio) despite dramatically changing his approach at the plate by being more aggressive early in counts and pulling more balls in the air. Whether it will ultimately lead to a better overall performance remains to be seen since it's tough to improve upon a lifetime .318 AVG and .401 OBP, but the new approach is more likely to generate power.

• Mauer is 13-for-34 (.382) against left-handed pitchers this year and has hit .296 with a .368 on-base percentage off lefties for his career. Among everyone since 1965 the only left-handed hitters with a higher career batting average and on-base percentage vs. left-handers than Mauer are Tony Gwynn, Rod Carew, Todd Helton, Larry Walker, and Wade Boggs. So three Hall of Famers and two near Hall of Famers who called Coors Field home. No platoon needed.

• Phil Hughes hasn't pitched particularly well, but his 0-4 record is misleading thanks to awful run support and he's performed better than he did through four starts last season:

YEAR GS ERA IP SO BB HR
2014 4 6.43 21 20 6 3
2015 4 4.39 27 22 2 6

Keeping the ball in the ballpark has been a career-long struggle for Hughes, so serving up six home runs in four starts certainly isn't a positive thing, but everything else is encouraging and Hughes really didn't start rolling last season until May.

• Kyle Gibson continues to be difficult to evaluate because for all the talk of his raw stuff being good he can't generate strikeouts and his control has been poor. Through four starts he has twice as many walks (12) as strikeouts (6) in 22 innings and his career strikeout rate of 5.1 per nine innings in a high-strikeout era puts him in the same category as guys like Scott Diamond, Joe Mays, and Nick Blackburn who couldn't sustain their early success.

• Casey Fien returning from a minor injury has really helped stabilize the bullpen after what was a horrendous start to the season. Not only is Fien clearly the best non-Glen Perkins option in the bullpen--he has a 3.47 ERA and 159/31 K/BB ratio in 169 innings for the Twins--counting on him as the primary setup man has allowed manager Paul Molitor to push replacement-level relievers like Blaine Boyer back into lower-leverage roles.

• On a related note, the sample size is very small but Perkins looks like his usual, pre-injury self after struggling mightily and then being shut down in September last season. His velocity is up, he's generating swinging strikes, and he's allowed just one run in eight innings while striking out eight and walking zero. Perkins, who's under team control through 2018, has a 2.84 ERA and 332 strikeouts in 317 career innings as a reliever.

• Danny Santana hit .319 as a rookie, but his inflated batting average on balls in play, bad plate discipline, and underwhelming track record all suggested he was over his head. Sure enough he's turned back into a pumpkin, hitting .210 with 20 strikeouts and zero walks in 15 games. Santana has 118 strikeouts and 19 walks in 116 total games for the Twins after averaging 91 strikeouts and 23 walks per 116 games at Double-A/Triple-A. That's not the approach of a leadoff man.

• Santana "leads" all American League hitters by swinging at 50 percent of the pitches he's seen outside of the strike zone. Kennys Vargas and Torii Hunter have swung at 40 percent of pitches outside the strike zone, giving the Twins three of the league's nine worst hackers. Santana is still very young and has plenty of talent, but there's a reason his rookie success came as such a big surprise after he hit just .273/.317/.391 in the minors.

• Ron Gardenhire is officially looking for another managing gig. He hired an agent for the first time in two decades and is said to be "willing to consider virtually any position." He's still being paid by the Twins in the final season of his contract, but Gardenhire figures to be a popular name brought up by fans and media members to replace managers on the hot seat. He has a 612-685 (.471) record, one 90-win season, four 90-loss seasons, and zero playoff wins since 2007.

• No. 1 prospect Byron Buxton and No. 2 prospect Miguel Sano are both hitting below .200 at Double-A after injury wrecked 2014 seasons, so don't expect to see that particular cavalry arriving at Target Field anytime soon. However, there's plenty of potential lineup and bullpen help playing well at Triple-A, including Aaron Hicks, Josmil Pinto, Michael Tonkin, and Lester Oliveros.

Paul Molitor barely has his feet wet as Twins manager, but one noticeable change from Ron Gardenhire is the willingness to platoon. In his 13 seasons as manager Gardenhire essentially never platooned based on handedness, instead treating left-handed bats like Jacque Jones and Jason Kubel as everyday players despite their inability to handle left-handers and ignoring the potential value mediocre right-handed bats like Danny Valencia had as lefty mashers.

Molitor platooned more in his first couple weeks than Gardenhire did in some seasons, regularly benching Oswaldo Arcia and Jordan Schafer against lefties. That's a positive sign in the sense that platooning is a very straightforward, commonplace method of squeezing the most value out of non-stars and putting players in a position to succeed, but in this case the Twins constructed such a weak bench that their platoon options are pretty unappealing.

Not playing Schafer against lefties is a good idea, but Shane Robinson is such a weak overall hitter that his right-handedness barely makes a difference. Not playing Arcia against lefties is also a good idea, at least in the short term, but if the Twins still hold out any hope of him developing into an everyday player he'll need playing time versus lefties eventually and Eduardo Escobar, while better than Robinson, isn't exactly an ideal platoon-mate for a corner outfielder.

Mostly, though, it's just nice to see a manager willing to embrace a common, effective tactic after more than a decade of watching lefties flail away against left-handed pitching, potentially useful righties cast aside because they struggled in everyday roles, and batting orders remain unchanged regardless of the handedness of the opposing pitcher. And if the Twins' bench ever contains better options Molitor could do some interesting things with the lineup.

It'd be great to have nine everyday players and just trot them out in the same lineup spots no matter who was on the mound, but it's hard to find teams that wouldn't benefit from at least some platooning. Nearly every left-handed hitter in baseball history with a sizable track record has fared better against righties than lefties, often to an extreme degree. Because of that, with a lefty on the mound even good left-handed hitters are often worse than mediocre right-handed hitters.

For instance, Joe Mauer and Justin Morneau are MVP-winning left-handed bats and two of the best hitters in Twins history. However, looking strictly at production against left-handed pitching they both have a lower career OPS than mediocre right-handed hitters like J.J. Hardy, Delmon Young, and Trevor Plouffe. Having the platoon advantage makes a huge difference. Here are the career splits for the Twins' most-used left-handed hitters of the Gardenhire era:

On average those six left-handed hitters have an .843 OPS versus righties and a .699 OPS versus lefties for a collective decrease of 17 percent and everyone but Denard Span sees their OPS drop more than 125 points. Those decreases are larger than typical across MLB, but in general lefties tend to be 10-15 percent worse versus lefties. Of course, some lefty bats are good enough overall that they warrant keeping in the lineup against lefties even with the decreased production.

Put another way: Mauer's production against lefties drops 18 percent, but he's still decent with a .749 OPS. However, not many lefties are as good as Mauer overall and so most warrant benching at least semi-regularly. Gardenhire obviously didn't agree. Jones hit .230/.278/.350 off lefties, yet Gardenhire played him every day and kept him leading off. Kubel hit .233/.305/.375 off lefties, yet Gardenhire played him every day and kept him in the middle of the lineup. You get the idea.

It's possible that Arcia will improve versus lefties and/or become productive enough overall that he's worth playing every day and because he's still just 24 years old it's certainly worth investing some more time into finding out. More likely is that he's ultimately a platoon or quasi-platoon player, which is less a knock on Arcia specifically and more just the way things tend to go with good but not great left-handed hitters.

Considering his poor defense Arcia needs to put up big numbers to be worth having in the lineup at an offense-heavy position. So far he's hit .221/.262/.340 off lefties, which is 25 percent worse than his .249/.322/.489 line off righties. Even if Arcia gets better versus righties and turns that 25-percent drop versus lefties into, say, a 15-percent drop it shouldn't be all that hard for the Twins to find a random right-handed hitter capable of better against lefties.

Aaron Hicks, while hugely disappointing overall, has posted a .758 OPS off lefties in the majors and has always hit lefties much better than righties in the minors. Hicks may never develop into a quality regular, but he's already a quality platoon option. With a lefty on the mound he's a viable center fielder and/or better than Arcia offensively and defensively in left field. And that's the magic of platooning, which turns useless into useful by separating strengths from weaknesses.

Molitor has shown the mindset required to improve a lineup via platooning, but the Twins need to actually give him the pieces to make those moves worthwhile and a four-man bench of Robinson, Escobar, Chris Herrmann, and Eduardo Nunez doesn't qualify. Still, after 13 years of learning to view hitters strictly through Gardenhire's binary "everyday player or not" lenses it's refreshing to consider how open-minded managing might take better advantage of useful but flawed options.

Topics for this week's "Gleeman and The Geek" episode included returning to the radio on KFAN, Trevor May's promising start, Joe Mauer's changed approach, Torii Hunter and Trevor Plouffe playing at extremes, Byron Buxton's timetable, Danny Santana turning back into a pumpkin, small crowds at Target Field, what to hope for with Ricky Nolasco, bumper music choices, and mailbag questions from listeners.

• "Gleeman and The Geek" is officially back on the radio, starting our fourth season on KFAN this Sunday at 4:00 pm. As always you can listen live on 100.3-FM and KFAN.com streaming audio or you can continue to listen to the show as a podcast via however you've been doing that already. We broadcast an hour live on the radio and then record another hour afterward in a side studio without any commercials, gluing the two pieces together for the final podcast product.

• Rob Neyer of FOXSports.com wrote about my NBCSports.com blog-mate Craig Calcaterra and the criticism that comes with criticizing other writers.

• A national security expert wrote in the Washington Post that MLB forcing fans at every ballpark to go through metal detectors is "pure security theater" and "laughable."

Shaq was never adamant about going to L.A. or any big market. He went to LSU, so it wasn't like he was saying, "I need to go to some big market." Our strategy wasn't to force anybody to go anywhere. Maybe if he was picked by Minnesota he might have said, "I don’t want to go there."

Instead the Wolves picked third, missing out on both O'Neal and Alonzo Mourning.